I want to find the right iptables commands combination to address the following need:

- NEs are NATed thru the linux box (using iptables) towards the WAN cloud, where the NTP servers are situated.- In order to achieve redundancy, the NTP Servers are in a load balancing cluster with one virtual IP address (172.30.4.245) - The problem is that when the NEs request for NTP updates using the 172.30.4.245, the NTP response is received from one of the actual IP addresses (.200, .230 .240).

Example:

The iptables is not allowing this flow, which is a normal behaviour since the requested vs responding address are not the same (172.30.4.245 vs 172.30.4.230) :